地塞米松对急性颅脑损伤患者血内NOS活性和NO产量的影响

目的 了解地塞米松（ＤＭ）对急性颅脑损伤（ＡＣＩ）患者围术期血内一氧化氮合成酶（ＮＯＳ）活性和一氧化氮（ＮＯ）产量的影响。方法 ２０例ＡＣＩ患者随机分为ＤＭ治疗组（于麻醉诱导前０．４ｍｇ／ｋｇＩＶ）和对照组，用分光光度法测定血清ＮＯＳ活性和ＮＯ产量。结果 术前两组ＮＯＳ、ＮＯ均高于下沉对照组，其中ＮＯＳ有显著性差异（Ｐ〈０．０１）。ＤＭ组自麻醉诱导前至开颅手术后２４小时（Ｔ０～Ｔ５）动态观察发现，ＮＯ、ＮＯＳ自始至终呈降低趋势；而对照组则呈显著性升高（ＮＯＴ１、Ｔ５，ＮＯＳＴ５），组间比较有显著性差异。结论 ＡＣＩ患者术前存在ＮＯＳ、ＮＯ代谢率乱，开颅手术后其含量进一步升高而加重脑缺血再灌注损伤。麻醉诱导时应用ＤＭ可显著抑制ＡＣＩ患者体内ｉＮＯＳ释放具有脑保护作用。可作为选择性ｉＤＯＳ拮抗剂在临床应用。

Effect of dexamethasone on nitric oxide synthase activity and nitric oxide outpu t in patients with acute cerebral injury

Objective To investigate effects of dexamethasone(DM) on nitric oxide synthase (NOS)activity and nitric oxide(NO)output in patients with acute cerebral injury(ACI)during neurosurgery.Methods Twenty patients with ACI were divided randomly into two groups (treated with DM group and control group).NOS activity and NO output were assayed with spectrophotometric analysis.Results NOS activity was significantly increased before anesthesia in patients with ACI compared to normal value( P <0 01).In DM group NOS activity and NO output appear a decrease tendency from T 0 to T 5.In control group NOS(T 5),NO(T 1T 5)were significantly increased( P <0 001).Conclusions There are NOS and NO metabolism disorder in patients with ACI.Surgical procedures on the brian may induce secondary cerebral ischemia causing neurologic injury.Terapeutic dosese of DM tersted before induction of anesthesia may significantly inhibite that iNOS activity and play a role in brain protection.